Gun flue coking retort oven



July 19, 1966 e. TUCKER, JR 3,261,763

GUN FLUE COKING RETORT OVEN Filed Aug. 27. 1963 2 Sheets-Sheet l FIG. 1

INVENTOR.

LIA/W000 6. TUCKER, .12.

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July 19, 1966 1.. G. TUCKER, JR

GUN FLUE COKING RETORT OVEN 2 Sheets-Sheet 2 Filed Aug. 27. 1963INVENTOR.

L/NWOOD G. THC/(5E, J2.

BY .(ZZinA FIG. 3

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United States Patent 3,261,763 GUN FLUE COKIN G RETORT OVEN Linwood G.Tucker, Jr., Pittsburgh, Pa., assignor to Koppers Company, Inc, acorporation of Delaware Filed Aug. 27, 1963, Ser. No. 304,928 1 Claim.(Cl. 202-141) This invention relates generally to coking retort ovensand more particularly to heating systems for high chambered gun flueovens of the horizontal type.

It is highly desirable that the coking chambers of a coke oven beincreased in capacity in order that the products of the ovens may becorrespondingly increased without a proportional increase in the capitalcost and the expense of the operation. Within certain limits, theefliciency of the coke oven battery and the return on the investmenttherein is increased by increasing the capacity of the ovens.

A recent trend has been towards the development or high chambered ovens.The extension of the height of coking chambers of coke oven batteriesrequires special provisions in order to supply suificient gas and air tothe heating flues and to elongate the combustion throughout the lengthof the flues to such uniform degree as is necessary to effect uniformcoking of the coal along a vertical plane.

It has been proposed heretofore to provide additional air or gas atintermediate points of the flues, but such arrangements have been eitherimpractical or attended with serious disadvantages. In such ovens, therehas been .an undesirable concentration of the heat of combustion of thefuel gas near the point in the flues at which the gas hasbeen introducedand the combustible mixture is formed. Such concentration producesunequal heating of the walls of the flame flues and unless compensatedfor, as by varying the thickness of the flue walls, the charge of cokein the adjacent oven chamber is coked at an uneven rate with respect tothe vertical height of the charge.

Heretofore it has been possible when using an underjet type ofhorizontal coke oven to reduce the concentration of the heat ofcombustion by introducing the gas at two levels; that is, by providinghigh and low burners in the flue. By utilizing high and low burners, thevariation in temperature over the height of the flue is reduced as thereare two vertically spaced heat sources. Some variation in temperaturecontinued to exist even with this expedient. The expedient of high andlow burners has never been successful in rich gas fed gun flue typehorizontal coke ovens because as rich gas is passed to the upper burnerit cracks due to the high temperatures imposed by the low burner. Thecracking of the rich gas results in carbon and resin deposition in thehigh burner duct. This deposition of carbon and resins clogs the highburner and the cracking reduces the heating value of the gas.

It is an object of the present invention to provide improved means forheating the coking chambers of rich gas fed gun flue type horizontalcoking retort ovens whereby the coking chambers may be of increasedheight, high and low burners can be used, and there is no resinous orcarbon deposition in the high burner. Further, the present inventionprovides a simple and eflicient means whereby a combustible mixture ofrich gas and air may be diluted, with the result that the flame ismaterially elongated and the rate of combustion throughout the height ofthe flame flue is substantially uniform. The present invention providessuch an arrangement and, in addition, the dilution of the combustiblemixture occurs automatically and without the introduction of gaseousmedia other than that required for combustion purposes.

In accordance with the present invention, I provide a gun flue coke ovenbattery having coking chambers that are of increased height and that areadequately heated by a system that provides substantially uniformtemperatures throughout the length of the flame flues. The heating wallsare provided with flame flues in which combustion occurs in two zonesand wherein no carbon or resin deposition occurs in the high burner.This is accomplished by the use of a high burner and a low burner.Separate gas guns supply the gas to the high and low burners. Duct meansare provided in the partition walls between the flame flues forrecirculating at least a portion of the gases of combustion in each ofthe flame flues of the heating walls. The recirculated waste gasesoperate todilute the combustible mixture, and the recirculation occursautomatically because of a pressure differential between the ends of therecirculation duct means. The pressure differential is caused by athermal siphoning eflect which is created by two columns of gas atdifferent densities in combination with an additional decrease in thegravity of the gases caused by the hot fuel gas addition through the gasnozzle.

The above and further objects and novel .features of the invention willappear more fully from the detailed description when the same is read inconjunction with the accompanying drawing. It is to be expresslyunderstood, however, that the drawings are not intended to be adefinition of the invention but are for the purpose of illustrationonly.

In the drawings wherein like parts are marked alike:

FIG. 1 is a transverse vertical cross sectional view through the heatingwall of a coke oven battery;

FIG. 2 is an enlarged cross sectional view showing one of the flamefines of the coke oven battery taken on line 2--2 of FIG. 4;

FIG. 3 is a vertical cross sectional view taken on line 3-3 of FIG. 2,and

FIG. 4 is a horizontal cross sectional view taken on lines 44 of FIG. 3.

Referring particularly to FIG. 1, a coke oven battery 10 which comprisesside walls 12 that are retained in position by buckstays 14, and a roof16 through which extend charging openings 20 for charging oven chambers22 with coal to be coked. Each oven chamber is also provided with a gasoff-take opening 24 that is connected by means of an ascension pipe 26to a collecting main 28. Cross-wise regenerators 30 are located beneaththe ovens and their cooperating heating walls, and are separated fromthe oven by horizontal brickwork 32. The crosswise regenerators 30extend throughout the width of the battery.

The coking chambers 22 are formed between spaced heating walls 34 (FIG.4) that extend transversely of the battery. Each of the heating walls 34is provided with a series of vertical flame flues 36 that extendthroughout the height of the wall and each flame flue is divided into alower section 38 and an upper section 40. Each flame flue includes ahigh burner and a low burner whereby combustion occurs in each of thesections 38 and 40. The lower section 38 of each of the flame flues 36is connected at the bottom portion thereof through ducts 42 in brickwork32 to the regenerator 30 that is beneath the respective heating wall.The duct 42 is employed for supplying the flame flue with or forconveying prodnets of combustion in accordance with the direction ofgases in the heating system.

The lower section 38 of each of the flame flues 36 is further providedat its lower end with a nozzle 44 which is connected through duct means46 to a gas gun 48 for supplying rich gas to the lower section 38 of theflame flue. As shown in FIGS. 1 and 4, the gas gun 48 extendshorizontally through the brickwork 32. The gas gun 48 is supplied withrich gas from a rich gas main 50 which supplies rich gas to all of thegas guns for the low burners 44 along the coke oven battery.

The upper section 40 of each flame flue 36 is connected to a second richgas nozzle 52 by means of a vertical duct 54 which directs the rich gasfrom the rich gas nozzle 52 to the lower end of the upper section 40.The vertical duct 54 extends through the lower section 38 of the flameflue 36 and the vertical duct 54 is positioned within a stepped portion56 of the dividing wall 58 between the flame flues 36.

Rich gas is supplied to burner 52 through duct 60 from gas gun 62 whichreceives the rich gas from rich gas main 64. The gas gun 62 suppliesrich gas to each of the high burners 52 and the rich gas is directedfrom the burner nozzle 52 through vertical duct 54 to the upper section40 of the flame flue 36.

In contrast to coke ovens built heretofore the buckstays 14 can bestraight I-beams without alterations. This is possible because of theuse of the two gas guns 48, 62 which pass through the walls 12 of theoven to the sides of the buckstays 14. The rich gas mains t), 64 can bepositioned at opposite sides of the coke oven as shown in FIG. 1, or inthe alternative the rich gas mains can each be disposed on the same sideof the oven.

A waste gas recirculation duct 66 is provided within each of thedividing walls 58. The waste gas recirculation duct 66 has an upperopening 63 into the flame flue near the top of the upper section 40thereof. At the lower end of the waste gas recirculation duct 66 theduct communicates by means of a passage 70 with the vertical duct 54described hereinabove.

The heating flues of each heating wall are operatively divided into fluegroups. Each group of flues communicates by means of a crossover duct'72 with a corresponding group of heating flues in an adjacent heatingwall and the so connected flue groups alternate periodically as flameflues and combustion product flues.

Combustion occurs upon the entrance of the heated gas and air to each ofthe flame flues and the gas burns upwardly therein as two distinctflames, a first flame emanating from the burner nozzle 44 in the lowersection 38 of the flame flue 36 and a second flame emanating from thevertical duct 54 and burning in the upper section 40 of the flame flue.The gases of combustion pass upwardly, a first portion passing outthrough crossover duct 72 and a second portion being drawn into thewaste gas recirculation ducts 66 at the upper entrance 68 of the latter.The waste gases flowing downwardly through the waste gas recirculationduct 66, through the connecting passage 70, and upwards in vertical duct54 and back into the flame flue 36 at the lower end of the upper section40 thereof.

The recirculation of the waste gases is caused by the thermal syphoningeffect which is created by two columns of gases at different densities.The waste gas in recirculation duct 66 is at a lower temperature andthus higher gravity than the combustion gases in the adjacent burningflue 36. This difference in densities will cause the waste gas inrecirculation duct 66 to flow vertically downward. The hot fuel gasaddition through the nozzle 62 at the base of vertical duct 54 willadditionally decrease the gravity of gases in recirculation duct 66which will further increase the rate of recirculation. The combinationof these two forces will create sufficient recirculation to en able thecoke oven gas to travel upwardly through vertical duct 54 without anycarbon formation. The specific construction of the duct system therebycombines a pressure differential with the aspirating effect induced bythe flow of rich gas through nozzle 52.

The return of waste gases to the flame flue 36 results in a dilution ofthe combustible mixture formed by the gas and air and thereby elongatesthe flame of combustion. The elongation of the flame equalizes thedistribution of heat throughout the height of the flame flue thusproviding an evenly heated heating wall 34- which results in evenlycoked coal in the coking chamber.

What is claimed:

In a coking retort oven having a plurality of flame flues in the wallseparating adjacent coking chambers and a plurality of dividing wallsseparating adjacent flame flues, the improvement comprising:

(a) a first low burner nozzle at the bottom of said flame (b) a secondhigh burner nozzle in the bottom of said flame flue and spaced apartfrom said first burner nozzle;

(c) a vertical first duct in a stepped portion of a fluedividing wallcommunicating with said second burner nozzle, said first vertical ductterminating in a high burner port intermediate the bottom and the top ofsaid flame flue; and

(d) a vertical second duct in said dividing wall communicating with theregion of said flame flue that is above said high burner port and theregion of said first duct adjacent said second nozzle burner whereby thegaseous products of combustion in the region of said flame flue abovesaid high burner port circulate downward in said second duct and mixwith and dilute the gaseous products of combustion formed at said secondnozzle burner.

References Cited by the Examiner UNITED STATES PATENTS 3,123,540 2/1964Van Ackeren 202141 FOREIGN PATENTS 577,126 6/ 1959 Canada. 407,664 1934Great Britain.

MORRIS O. WOLK, Primary Examiner.

JAMES H. TAYMAN, JR., Examiner.

